Rod reducer, compressor, distractor system

ABSTRACT

A compressor/distractor system for operating on a spine is disclosed. The system includes two rod reducers which each advance a spinal rod into the shoulder portion of a pedicle screw. Each rod reducer includes an inner member, an outer member, and a pair of gripping members. Each outer member receives and advances the spinal rod into the pedicle screw. The outer member also includes a through slot which receives the proximal end of each of the pair of gripping members which may limit the longitudinal translation of the outer member with respect to the inner member. The compressor/distractor system may include a compressor/distractor device which has a compressing, a distracting, and a neutral configuration. A method for using the minimally invasive rod reducers with the compressor/distractor system to secure at least two pedicle screws in desired positions on a spinal rod is also disclosed.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of, and priority to, U.S.Provisional Application Ser. No. 61/586,928, filed on Jan. 16, 2012, thecontents of which is incorporated herein by reference in is entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to a system and method for operating onthe spine. More particularly, the present disclosure relates to aminimally invasive rod reducer, compressor/distractor system, and amethod for using the compressor/distractor system to deliver a spinalrod to the head of a pedicle screw.

2. Background of Related Art

The spinal column is a complex system of bones and connective tissuesthat provide support for the human body and protection for the spinalcord and nerves. The adult spine is comprised of an upper and lowerportion. The upper portion contains 24 discrete bones, which aresubdivided into three areas including 7 cervical vertebrae, 12 thoracicvertebrae and 5 lumbar vertebrae. The lower portion is comprised of thesacral and coccygeal bones. The cylindrical shaped bones, calledvertebral bodies, progressively increase in size from the upper portiondownwards to the lower portion.

An intervertebral disc along with two posterior facet joints cushion anddampen the various translational and rotational forces exerted upon thespinal column. The intervertebral disc is a spacer located between twovertebral bodies. The facets provide stability to the posterior portionof adjacent vertebrae. The spinal cord is housed in the canal of thevertebral bodies. It is protected posteriorly by the lamina. The laminais a curved surface with three main protrusions. Two transverseprocesses extend laterally from the lamina, while the spinous processextends caudally and posteriorly. The vertebral bodies and lamina areconnected by a bone bridge called the pedicle.

The spine is a flexible structure capable of a large range of motion.There are various disorders, diseases, and types of injury whichrestrict the range of motion of the spine or interfere with importantelements of the nervous system. The problems include, but are notlimited to scoliosis, kyphosis, excessive lordosis, spondylolisthesis,slipped or ruptured discs, degenerative disc disease, vertebral bodyfracture, and tumors. Persons suffering from any of the above conditionstypically experience extreme or debilitating pain and often timesdiminished nerve function. These conditions and their treatments can befurther complicated if the patient is suffering from osteoporosis, orbone tissue thinning and loss of bone density.

Spinal fixation apparatuses are widely employed in surgical processesfor correcting spinal injuries and diseases. When the disc hasdegenerated to the point of requiring removal, there are a variety ofinterbody implants that are utilized to take the place of the disc.These include polyetheretherketone (“PEEK”) interbody spacers, metalcages, and cadaver and human bone implants. In order to facilitatestabilizing the spine and keeping the interbody in position, otherimplants are commonly employed, including longitudinally linked rodssecured to coupling elements, which in turn are secured to the bone byspinal bone fixation fasteners such as pedicle screws, hooks, andothers. The opposing pair of longitudinally linked rods is commonlydisposed along the long axis of the spine via a posterior approach.Pedicle screws are utilized to capture these rods and can bemanufactured from any biocompatible material, including cobalt chrome,stainless steel, titanium, and PEEK. It is desired to perform theseprocedures in a minimally invasive manner to minimize pain and reducerecovery time for the patient. Therefore, a need exists for a minimallyinvasive rod reducer, compressor, distractor system that can deliver therod into the head of the pedicle screw or bone anchor while maintainingthe proper screw and rod construct alignment.

A rod reducer that is small enough in diameter to work with a minimallyinvasive retractor, such as the rod reducer disclosed in U.S. patentapplication Ser. No. 13/595,533, the contents of which are herebyincorporated by reference in their entirety and a minimally invasiveretractor, such as the minimally invasive retractor disclosed in U.S.Pat. No. 7,846,093, the contents of which are hereby incorporated byreference in their entirety, are also disclosed.

SUMMARY

The present disclosure is directed towards a system for operating on thespine. The system includes pedicle screws, rod reducers, and a forceapplying device.

According to one aspect, the rod reducers include a proximal end and adistal end and define a longitudinal axis between the proximal anddistal ends. The rod reducer includes an outer member and an innermember. The inner member is selectively attachable to the housing of thepedicle screw. The outer member is axially movable relative to the innermember when the inner member is secured to the housing of the pediclescrew to secure the spinal rod within the saddle of the housing of thepedicle screw. The outer member includes a proximal segment and a distalsegment. The proximal segment is rotatable for axially translating thedistal segment. The distal segment is engageable with the spinal rod tosecure the spinal rod within the saddle upon the axial translation ofthe distal segment. The proximal segment independently rotates relativeto the distal segment. The rod reducer includes a pair of grippingmembers configured to engage the housing of the pedicle screw. The pairof gripping members is positioned between the inner and outer members ofthe rod reducer.

The handle assembly is selectively engageable with the rod reducer tomove the outer member of the rod reducer axially relative to the innermember of the rod reducer. The handle assembly is configured to rotatethe outer member so that the rotational movement of the outer memberaxially moves the outer member relative to the inner member. The handleassembly includes a turning handle and an anti-torque handle. Theanti-torque handle is selectively engageable with the proximal end ofthe rod reducer and the turning handle is selectively engageable with aproximal end of the anti-torque handle.

In another aspect, an embodiment of the system includes two rodreducers, a force applying device, and a fulcrum. The force applyingdevice is configured for selectively engaging each rod reducer. Thesystem may also include at least one minimally invasive retractiondevice.

In yet another aspect, the force applying device is acompressor/distractor device including a first hook member, a secondhook member, and a body portion. The body portion has a first end and atrack extending from the first end. The first end includes the firsthook member in a fixed position. The first end may slidably receive thefirst hook member in a fixed position. The track includes a set of teethand is configured for slidably receiving the second hook member.

The second hook member includes a switch assembly and a gear assembly.The second hook member traverses the track when the gear assembly isrotated. The gear assembly may also retain the second hook member withinthe track. The switch assembly permits the second hook member totraverse the track in a desired direction, towards the first hook memberor away from the first hook member. The switch assembly may alsorestrain the second hook member from traversing the track in anundesired direction.

The first and second hook members may be configured in a compressingconfiguration to engage the two rod reducers such that rod reducers arebetween the hook members. The first and second hook members may also beconfigured in a distracting configuration to engage the rod reducerssuch that the hook members are between the rod reducers.

The fulcrum is configured to receive the proximal segment of the outermember of each rod reducer and remain in a fixed position on thelongitudinal axis of each rod reducer.

According to still another aspect, a method for compressing ordistracting vertebrae including two minimally invasive rod reducers, acompressor/distractor system, a spinal rod, and two pedicle screws. Themethod includes the steps of accessing the spinal area of a patienthaving at least two pedicle screws secured to respective vertebrae,engaging each pedicle screw with a rod reducer, advancing the spinal rodinto the head of each pedicle screw, attaching a compressor/distractordevice to each rod reducer, inserting a set screw through each rodreducer, manipulating the compressor/distractor device, and securing thespinal rod to each pedicle screw.

The method may also include the step of attaching a fulcrum to theproximal segment of each outer member before rotating the gear assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the disclosureand, together with a general description of the disclosure given above,and the detailed description of the embodiments given below, serve toexplain the principles of the disclosure, wherein:

FIG. 1A is a perspective view of a minimally invasive rod reducer inaccordance with the principles of the present disclosure beforeengagement with a rod and a pedicle screw;

FIG. 1B is a perspective view of the rod reducer of FIG. 1A afterinitial engagement of the rod and pedicle screw;

FIG. 1C is a perspective view of the rod reducer of FIG. 1B after therod has been received by the shoulder portion of the pedicle screw

FIG. 2 is a perspective view of the outer member of FIG. 1A;

FIG. 3 is a exploded view of the outer member of FIG. 2;

FIG. 4 is a bottom cross-sectional view of the outer member of FIG. 2taken along the section line 4-4;

FIG. 5 is an exploded view of the rod reducer of FIG. 1A;

FIG. 6 is a side cross-sectional view of the of the rod reducer of FIG.1A;

FIG. 6A is an enlarged view of the detail area 6A of FIG. 6;

FIG. 7A is a perspective view of the outer member of FIG. 2 engaged witha turning handle and an anti-torque handle;

FIG. 7B is an exploded view of FIG. 7A;

FIG. 8 is a perspective view of an embodiment of a compressor/distractorsystem in accordance with the principles of the present disclosure in acompressing configuration;

FIG. 9 is a perspective view of the compressor/distractor system of FIG.8 in a distracting configuration;

FIG. 10A is a perspective view of another embodiment of acompressor/distractor system in accordance with the principles of thepresent disclosure in a compressing configuration;

FIG. 10B is a perspective view of the compressor/distractor system ofFIG. 10A in a distracting configuration;

FIG. 11 is a perspective view of the fulcrum of FIG. 9;

FIG. 11A is an exploded view of the fulcrum of FIG. 11;

FIG. 11B is a top view of the fulcrum of FIG. 11;

FIG. 11C is a side cross-sectional view of the fulcrum taken along thesection line 11C-11C in FIG. 11B;

FIG. 12 is an enlarged view of the compressor/distractor device of FIG.9;

FIG. 13 is a top view of the compressor/distractor device of FIG. 12;and

FIG. 14 is an exploded view of the compressor/distractor device of FIG.12.

DETAILED DESCRIPTION OF THE DRAWINGS

Particular embodiments of the present disclosure will be describedherein with reference to the accompanying drawings. As shown in thedrawings and as described throughout the following description, and asis traditional when referring to relative positioning on an object, theterms “proximal” and “trailing” may be employed interchangeably, andshould be understood as referring to the portion of a structure that iscloser to a clinician during proper use. The terms “distal” and“leading” may also be employed interchangeably, and should be understoodas referring to the portion of a structure that is farther from theclinician during proper use. In addition, the term “cephalad” or“cranial” is used in this application to indicate a direction toward apatient's head, whereas the term “caudad” indicates a direction towardthe patient's feet. Further still, the term “medial” indicates adirection toward the middle of the body of the patient, whilst the term“lateral” indicates a direction toward a side of the body of the patient(i.e., away from the middle of the body of the patient). The term“posterior” indicates a direction toward the patient's back, and theterm “anterior” indicates a direction toward the patient's front. In thefollowing description, well-known functions or constructions are notdescribed in detail to avoid obscuring the present disclosure inunnecessary detail.

Turning now to FIGS. 2-6A, a rod reducer 10 includes an outer member 20,an inner member 30, and a pair of gripping members 40, such as the rodreducer disclosed in U.S. patent application Ser. No. 13/595,533 whichis incorporated by reference. Outer member 20 includes a proximalsegment 21, a distal segment 22, and a ring member 27 that is disposedbetween proximal and distal segments 21, 22. Proximal segment 21includes an engaging portion 21 a at a distal end of proximal segment 21and a gripping portion 21 b at a proximal end of proximal segment 21. Aninner surface 28 of proximal segment 21 is threaded. Distal segment 22defines a slot 26 therethrough and includes a reducing portion 22 a at adistal end of distal segment 22 and a receiving portion 22 b at aproximal end of distal segment 22. Receiving portion 22 b includes aplurality of gripping features 22 c on an outer surface of receivingportion 22 b. A pair of rod engaging slots 25 and a pair of grippingmember receiving slots 24 are defined through reducing portion 22 a.Receiving portion 22 b of distal segment 22 is configured to receiveengaging portion 21 a of proximal segment 21 so that ring member 27 isdisposed between proximal and distal segments 21, 22. The components ofouter member 20 may be integrally formed or assembled.

Inner member 30 includes an elongate body member 39 that defines anannular recess 33 configured to receive the pair of gripping members 40so that the gripping members 40 are disposed in opposition on theelongate body member 39. Inner member 30 includes a pair of arms 32supported on a distal end of elongate body member 39. A proximal end ofelongate body member 39 has a threaded arrangement 38 that mates withthreaded inner surface 28 of proximal segment 21 of outer member 20 toaxially advance outer member 20 relative to inner member 30 as will bedescribed in greater detail below.

Each gripping member 40 includes a body 47 having a supporting member43, a proximal finger 46, and a distal finger 45. Supporting member 43is configured to engage annular recess 33 of inner member 30 to supportbody 47 of each gripping member 40 on inner member 30. Proximal finger46 extends proximally from supporting member 43 and is slidablypositionable within slot 26 of outer member 20. Distal finger 45 extendsdistally from supporting member 43 and is positionable between an arm 32of inner member 30 and reducing portion 22 a of outer member 20 so thatdistal finger 45 is substantially aligned with a gripping memberreceiving slot 24 of reducing portion 22 a.

As illustrated in FIGS. 1A-1C, outer member 20 of rod reducer 10 isdisposed in a proximal position relative to inner member 30 of rodreducer 10, distal fingers 45 of gripping member 40 of rod reducer 10are secured to an outer surface of pedicle screw head 910. Proximalsegment 21 of outer member 20 may then be rotated by virtue of thethreaded arrangement between outer member 20 and inner member 30 foraxially advancing distal segment 22 of outer member 20 relative to innermember 30 and proximal segment 21. Proximal segment 21 remains axiallyfixed when rotated. Notably, as proximal segment 21 rotates, distalsegment 22 remains radially fixed as distal segment 22 axiallytranslates relative to inner member 30 and proximal segment 21. Outermember 20 approximates a spinal rod 800 positioned between rod reducer10 and pedicle screw 900 as outer member 20 is advanced toward pediclescrew 900 to secure spinal rod 800 within a saddle 912 of pedicle screw900. As outer member 20 advances distally, a proximal end of slot 26 ofouter member 20 approximates a proximal end of proximal fingers 46 ofgripping member 40.

Turning now to FIGS. 7A and 7B, a rod reducer and handle assembly 650includes the rod reducer 10 and a handle assembly 652. Handle assembly652 includes a turning handle 600 and an anti-torque handle 700 that areselectively connectable to gripping portion 21 b and gripping features22 c respectively on rod reducer 10. Turning handle 600 includes a shaft610, a handle 620, and a socket 630 that defines an opening 632. Opening632 is configured to receive a proximal end of gripping portion 21 b ofrod reducer 10. Handle 620 is secured to a proximal end of shaft 610 anda socket 630 that may be integrally formed is secured to a distal end ofshaft 610. Anti-torque handle 700 includes a shaft 720 and a handle 710that may be integrally formed. Shaft 720 includes a socket 722 thatdefines an opening 722 a at a distal end of socket 722. Opening 722 a isdisposed in communication with a lumen 725 defined within shaft 720 andanother opening 724 disposed at a proximal end of shaft 720 so thatanti-torque handle 700 may slide over gripping portion 21 b of rodreducer 10 and engage with gripping feature 22 c of rod reducer 10 toprevent rotational movement of distal segment 22 of outer member 20 ofrod reducer 10.

Thus, if needed, either or both the turning handle 600 and theanti-torque handle 700 may be used to facilitate the rotational movementof outer member 20 relative to inner member 30. In particular, rotationof turning handle 600 imparts rotational movement to proximal segment 21of outer member 20 and anti-torque handle 700 imparts counter rotationalmovement to distal segment 22 of outer member 20 so that proximalsegment 21 rotates and distal segment 22 axially translates withoutrotating. As appreciated, anti-torque handle 700 is configured to limitthe amount of torque imparted from the rotational movement imparted byturning handle 600 to prevent undesirable torquing of the outer member20. More particularly, anti-torque handle 700 slides down over the outersurface of outer member 20 of rod reducer 10 so that a distal end ofanti-torque handle 700 engages distal segment 22 of outer member 20 anda proximal end of proximal segment 21 of outer member 20 is exposed forengagement with turning handle 600. Meanwhile, since gripping member 40is secured within annular recess 33 of inner member 30 such thatproximal finger 46 of gripping member 40 is supported in slot 26 ofdistal segment 22 of outer member 20, the engagement of anti-torquehandle 700 with gripping feature 22 c of distal segment 22 of outermember 20 prevents rotation of both distal segment 22 of outer member 20and inner member 30 as proximal segment 21 of outer member 20 is rotatedwith turning handle 600. After spinal rod 800 is fully reduced into thesaddle 910 of pedicle screw 900, turning handle 600 and anti-torquehandle 700 may be removed and a set screw (not shown) may be inserteddown an inner diameter of rod reducer 10 to lock spinal rod 800 intoplace. Alternatively, anti-torque handle 700 may also be used to preventrotation when tightening the set screw after spinal rod 800 has beenfully reduced. Rod reducer 10 may then be removed.

Referring now to FIGS. 8 and 9, a compressor/distractor system 200includes rod reducers 10, a compressor/distractor device 210, and afulcrum 300. System 200 may further include one or more minimallyinvasive retraction devices 950, such as the retractor disclosed in U.S.Pat. No. 7,846,093, the entire contents of which is incorporated byreference. Each of the two rod reducers 10 engages a respective pediclescrew 900. Each pedicle screw 900 is inserted into a respective vertebraand is configured to receive spinal rod 800 in saddle portion 912 asshown in FIG. 1C. Compressor/distractor device 210 is configured forselective engagement with each rod reducer 10 when each rod reducer 10is attached to pedicle screw 900.

FIGS. 10A and 10B illustrate other embodiments of compressor/distractorsystem 200 a using compressor 400 and distractor 500 respectively as theforce applying device. As shown in FIG. 10A, the compressor 400 has ahandle assembly 410 with handles 402, 404 that are pivotably coupledtogether by pivot pin 406. Distal portions of handles 402, 404 haverespective grippers 402 a, 404 a for engaging rod reducers 10. Eachgripper 402 a, 404 a includes an arcuate recess configured for engagingan outer surface of rod reducer 10. Compressor 400 also includes an arm420 having teeth 422 disposed thereon. Teeth 422 releasably engage adistal portion of handle 404 for maintaining a predetermined distance orspacing between handles 402, 404 during a compression stroke that movesrod reducers 10 towards each other. The arm 420 is pivotably coupled toa distal end of arm 402 such that it can be repositioned and allowhandles 402, 404 to be moved away from each other once the desiredamount of compression is achieved. Similarly, as shown in FIG. 10B, thedistractor 500 has a handle assembly 510 with handles 502, 504 that arepivotably coupled together by pivot pin 506. Distal portions of handles502, 504 have respective grippers 502 a, 504 a for engaging rod reducers10. Each gripper 502 a, 504 a includes an arcuate recess configured forengaging an outer surface of rod reducer 10. Distractor 500 alsoincludes an arm 520 having teeth 522 disposed thereon. Teeth 522releasably engage a distal portion of handle 502 for maintaining apredetermined distance or spacing between handles 502, 504 during adistraction stroke that moves rod reducers 10 away from each other. Thearm 520 is pivotably coupled to a distal end of arm 504 such that it canbe repositioned and allow handles 502, 504 to be moved away from eachother once the desired amount of distraction is achieved.

Now referring to FIGS. 11-11C illustrating fulcrum 300 including throughholes 315 which receive inner bearing rings 320 which house retainingrings 330 that are prevented from falling out of fulcrum 300 by caps340. Fulcrum 300 is an elongate structure and each through hole 315includes an annular groove for retaining inner bearing rings 320 andtheir respective retaining rings 330.

Referring now to FIGS. 12-14, compressor/distractor device 210 has afirst hook member 220, a second hook member 230, and a body portion 260.Body portion 260 includes first end 261 and track 262 extending fromfirst end 261 along a length of body portion 260. Track 262 includes aset of teeth 263 and sidewall 264. First end 261 is insertable into arecess of the first hook member 220 and is fixed in position at firstend 261 of body portion 260 by the cooperation of retaining pin 221 andfirst end retaining ring 222.

First and second hook members 220, 230 may each include hook portions224, 234 for engaging rod reducers 10. Hook portions 224, 234 haverespective distracting hooks 225, 235 and compressing hooks 226, 236.When rod reducers 10 are between first and second hook members 220, 230,each compressing hook 226, 236 engages a rod reducer 10 in a compressingconfiguration of compressor/distractor device 210 (FIG. 8). When firstand second hook members 220, 230 are between rod reducers 10, eachdistracting hook 225, 235 engages a rod reducer 10 in a distractingconfiguration of compressor/distractor device 210 (FIG. 9).Compressor/distractor device 210 may also have a neutral configuration.Each hook member 220, 230 may engage gripping features 22 c of each rodreducer 10.

Second hook member 230 may include a switch assembly 250 and a gearassembly 240. Switch assembly 250 may include a pawl 251, a pawl switchpin 252, a switch cap 253, a spring 254, a ball 255, ball detents 258, aswitch 256, and a switch shaft 257. Switch assembly 250 is selectableamongst a first condition, a second condition, and a third condition.Each condition may correspond to a configuration of thecompressor/distractor device 210. In the first condition, switchassembly 250 restrains second hook member 230 from traversing track 262towards the first hook member 220, while permitting second hook member230 to traverse track 262 away from the first hook member 220 (i.e., adistracting configuration). In the second condition, switch assembly 250restrains second hook member 230 from traversing track 262 away from thefirst hook member 220, while permitting second hook member 230 totraverse track 262 towards the first hook member 220 (i.e., acompressing configuration). In the third condition, switch assembly 250allows the second hook member 230 to freely move along track 262 ineither direction (i.e., a neutral configuration), which allows for quickadjustment of compressor/distractor device 210.

Switch 256 rotates about switch shaft 257 causing pawl pivot pin 252 torotate pawl 251 about switch shaft 257. Pawl pivot pin 252 acts on pawl251 causing pawl 251 to engage set of teeth 263 which restrains secondhook member from traversing in the undesired direction.

Second hook member 230 may include ball detents 258. Each ball detent258 corresponds to a position of switch 256. Switch 256 may be retainedin each position by spring 254 pressing ball 255 into a correspondingball detent 258. Ball 255 selectively engages each ball detent 258 whenthe switch is in one of the positions corresponding to the compressing,distracting, and neutral configurations of the compressor/distractordevice 210.

Gear assembly 240 engages set of teeth 263 causing second hook member230 to traverse track 262. Rotation of traversing screw 244 rotatespinion 242. The cooperation of pinion 242 with set of teeth 263 inducesthe second hook member 230 to traverse track 262. A drive tool (notshown) may engage and rotate traversing screw 244.

A method for using system 200 to manipulate a vertebra into a desiredposition with respect to a second vertebra is discussed below. First, asurgeon accesses the spinal area of a patient having at least twopedicle screws 900 secured to adjacent vertebrae (not shown). Eachpedicle screw 900 may be engaged by a minimally invasive retractiondevice 950. The surgeon then engages each pedicle screw 900 with a rodreducer 10 by attaching inner member 30 to pedicle screw head 910 asshown in FIG. 1B. Each inner member 30 receives a respective pediclescrew head 910 between arms 32. Next, the surgeon advances an outermember 20 along each inner member 30 by rotating the distal segment 21of the outer member 20. The surgeon may use handle assembly 650 torotate distal segment 21.

Rod engaging slots 25 of proximal segment 22 of each outer member 20receives a portion of rod 800 and advances rod 800 into saddle portion912 of each pedicle screw 900 as shown in FIGS. 1B and 1C. Once eachouter member 20 is fully advanced with respect to each inner member 30as shown in FIG. 1C, the surgeon engages each outer member 20 with aforce applying device 210, 400, 500 as shown in FIGS. 8-10B. The forceapplying device may include gear assembly 240. Then the surgeon insertsa set screw (not shown) through each rod reducer 10 for securing the rod800 to each pedicle screw 900. The surgeon may rotate at least one ofthe set screws to either partially or fully secure rod 800 to at leastone of the pedicle screws 900.

Then the surgeon manipulates gear assembly 240 until each pedicle screw900 is in a desired position on rod 800. Manipulation of gear assembly240 may include rotating traversing screw 244. The surgeon may use adrive tool to manipulate gear assembly 240.

Then the surgeon rotates each set screw to fully secure rod 800 to eachpedicle screw 900 in the desired position. Then the surgeon may removecompressor/distractor device 210 and each rod reducer 10.

The surgeon may also attach fulcrum 300 to gripping portion 21 b ofproximal segment 21 of each outer member 20 before manipulating gearassembly 240. Fulcrum 300 may then be removed with thecompressor/distractor device 210 and each of the rod reducers 10.

While several embodiments of the disclosure have been shown in thedrawings, it is not intended that the disclosure be limited thereto, asit is intended that the disclosure be as broad in scope as the art willallow and that the specification be read likewise. Therefore, the abovedescription should not be construed as limiting, but merely asexemplifications of particular embodiments. Those skilled in the artwill envision other modifications within the scope and spirit of theclaims appended hereto.

What is claimed:
 1. A compressor/distractor system comprising: two rodreducers each including a proximal end and a distal end and defining alongitudinal axis between the proximal and distal ends, each rod reducerincluding an outer member and an inner member, the inner member beingselectively attachable to a head of a pedicle screw, the outer memberbeing axially movable relative to the inner member when the inner memberis secured to the head of the pedicle screw to secure a spinal rodwithin a saddle portion of the head of the pedicle screw; a forceapplying device which selectively engages each of the two rod reducers,the force applying device including first and second hook members, theforce applying device having a compressing configuration when the firstand second hook members engage the two rod reducers with the rodreducers positioned between the first and second hook members and havinga distracting configuration when the first and second hook membersengage the two rod reducers with the first and second hook memberspositioned between the two rod reducers; and a fulcrum which engages theproximal end of each of the two rod reducers and remains in a fixedposition on the longitudinal axis of each of the two rod reducers. 2.The compressor/distractor system of claim 1, wherein the second hookmember has a switch assembly and a gear assembly, and wherein the forceapplying device includes a body portion having a first end and a trackextending from the first end, the first end having the first hook memberin a fixed position, the track having a set of teeth and configured toslidably receive the second hook member, the second hook membertraverses the track when the gear assembly cooperates with the set ofteeth, the switch assembly selectively engages the set of teethrestraining the second hook member from traversing the track in a firstdirection.
 3. The compressor/distractor system of claim 2, wherein thefirst and second hook members engage a gripping portion on each rodreducer.
 4. The compressor/distractor system of claim 2, wherein thegear assembly includes a pinion which cooperates with the set of teethand receives a screw which rotates the pinion.
 5. Thecompressor/distractor system of claim 2, wherein the switch assemblyincludes a switch, a pawl having a pawl pivot pin, and a switch shaft,the rotation of the switch causes the pawl pivot pin to rotate the pawlabout the switch shaft.
 6. The compressor/distractor system of claim 5,wherein the rotation of the pawl about the switch shaft causes the pawlto engage the set of teeth restraining the second hook member fromtraversing the track in the first direction.
 7. Thecompressor/distractor system of claim 1, wherein the fulcrum includes aplurality of through holes, each of the through holes configured toreceive the distal end of each rod reducer.
 8. The compressor/distractorsystem of claim 1, wherein a distance defined between the fixed positionon the longitudinal axis of each of the two rod reducers engaged by thefulcrum is constant when the force applying device compresses anddistracts the rod reducers relative to one another.
 9. Thecompressor/distractor system of claim 1, wherein each of the first andsecond hook members has a hook portion including a distracting hook anda compressing hook.
 10. A compressor/distractor system comprising: tworod reducers each including a proximal end and a distal end and defininga longitudinal axis between the proximal and distal ends, each rodreducer including an outer member and an inner member, the inner memberbeing selectively attachable to a head of a pedicle screw, the outermember being axially movable relative to the inner member when the innermember is secured to the head of the pedicle screw to secure a spinalrod within a saddle portion of the head of the pedicle screw; a forceapplying device which selectively engages each of the two rod reducers,the force applying device including: a first hook member; a second hookmember having a switch assembly and a gear assembly; and a body portionhaving a first end and a track extending from the first end, the firstend having the first hook member in a fixed position, the track having aset of teeth and configured to slidably receive the second hook member,the second hook member traverses the track when the gear assemblycooperates with the set of teeth, the switch assembly selectivelyengages the set of teeth restraining the second hook member fromtraversing the track in a first direction, wherein the force applyingdevice has a compressing configuration, a distracting configuration, anda neutral configuration and the second hook member includes ball detentseach corresponding to a first, a second, and a third position of theswitch assembly, each position of the switch assembly corresponding to arespective configuration of the force applying device; and a fulcrumwhich engages the proximal end of each of the two rod reducers andremains in a fixed position on the longitudinal axis of each of the tworod reducers.
 11. The compressor/distractor system of claim 10, whereinthe switch assembly includes a spring and a ball, the spring mounted tothe switch and configured to press the ball into the ball detents, theball selectively engages a ball detent when the switch is in eachposition.
 12. A compressor/distractor system comprising: two rodreducers each including a proximal end and a distal end and defining alongitudinal axis between the proximal and distal ends, each rod reducerincluding an outer member and an inner member, the inner member beingselectively attachable to a head of a pedicle screw, the outer memberbeing axially movable relative to the inner member when the inner memberis secured to the head of the pedicle screw to secure a spinal rodwithin a saddle portion of the head of the pedicle screw; a forceapplying device which selectively engages each of the two rod reducers,the force applying device including: a first hook member having a hookportion including a distracting hook and a compressing hook; a secondhook member having a switch assembly, a gear assembly and a hook portionincluding a distracting hook and a compressing hook; and a body portionhaving a first end and a track extending from the first end, the firstend having the first hook member in a fixed position, the track having aset of teeth and configured to slidably receive the second hook member,the second hook member traverses the track when the gear assemblycooperates with the set of teeth, the switch assembly selectivelyengages the set of teeth restraining the second hook member fromtraversing the track in a first direction; and a fulcrum which engagesthe proximal end of each of the two rod reducers and remains in a fixedposition on the longitudinal axis of each of the two rod reducers.